The present invention relates to an electrically controlled multifeed circular knitting machine and in particular to a method and apparatus for determining the specific needle placed at any given feed system and for controlling the output of the pattern matrix in accordance therewith.
In multifeed knitting machines having electronic patterning devices, particularly in small diameter circular knitting machines, the needles are divided into separate knitting systems with independent yarn feeds each system having electrically operated means, such as an electromagnet, for selectively actuating the needles. The actual electromagnetic selectors for each of the separate knitting feeds are distributed about the circumference of the needle cylinder of the machine so as not to interfere with each other. A storage or recording matrix is provided which contains the patterning information for each knitting group or system of needles, with respect to its wale and course. A reading device is further provided to activate the output of the matrix with respect to the position of the needles in each of the knitting systems. The reading device is connected to a unidirectional counter which determines the passage of the needles during the knitting operation so that the output of the pattern storage or recording matrix and the needles can be synchronized. The output of the recording or storage matrix is connected to each of the electromagnets and must therefore be properly synchronized since, because of the distribution of the electromagnets about the needle cylinder, a different needle is positioned, at any one time, at each of the electromagnets.
The synchronization of the recording or storage system with respect to the particular electromagnets does not present a major problem when the record of the pattern is contained either on punched tapes, magnetic tapes or film tapes, since such tapes can store greater amounts of information. However, when fixed memory matrices, having small capacity, are employed, particularly in small diameter circular knitting machines, the matrices are provided with a coded record which allows a single memory unit to be employed for more than one feed system. This use of a coded record increases the capacity of the small fixed memory matrices but requires that the coded output be changed and converted into an independent output for each of the separate knitting feed systems. At least one of the coded outputs, i.e.: the output controlling the needle in any other than the basic or prime feed system, must be delayed in its transmittal to the electromagnetic needle selecting means by an amount equal to the angle of rotation of the needle cylinder corresponding to the number of needles between the point at which the needles are actually counted and the point at which the electromagnetic selecting means is located to which the coded output is transmitted. In general, the coded output from fixed matrices is fed first to a shift register, the length between shifts being equal to the number of spaces between the knitting feed or selecting points. The shift being performed by a clock pulse derived from the needle sensor itself.
The disadvantage of the method as mentioned above consists in that there is either a need for a large capacity pattern memory or storage means, or the necessity of using multiple shift registers for each knitting feed. In both instances, complex expensive devices must be provided. This being a decided disadvantage particularly when more than one knitting machine is controlled from a single memory bank.
It is an object of the present invention to overcome each of the disadvantages noted and to provide a simple versatile memory reading and electronic control system for selectively actuating the needles in a multifeed knitting system.
The foregoing objects, other objects, and the advantages of the present invention will become obvious from the following disclosure of the present invention and its primary embodiment.